diff --git a/src/diana/sgfparser/__init__.py b/src/diana/sgfparser/__init__.py
--- a/src/diana/sgfparser/__init__.py
+++ b/src/diana/sgfparser/__init__.py
@@ -1,4 +1,9 @@
 def skip_whitespace(s, start):
+	"""Find the first non-whitespace character in a string.
+
+	:param str s: an input string
+	:param int start: an index where the search starts
+	:return: index of the first non-whitespace character or len(s)"""
 	i = start
 	while i < len(s) and s[i].isspace():
 		i += 1
@@ -7,6 +12,12 @@ def skip_whitespace(s, start):
 
 
 def str_row_col(s, i):
+	"""Translate a string index i to a row and col number.
+
+	:param str s: an input string
+	:param int i: an index pointing into s
+	:return: a string position as (row, col)
+	:rtype: (int, int)"""
 	k = 0
 	(r, c) = (0, 0)
 	for (r, line) in enumerate(s.splitlines(True)):